Input Observer Input Observer

Abigail C. Evans
Jacob O. Wobbrock
University of Washington


Current Version 2.1.2

Download Quick Start Guide

Windows executable:
Mechanical Turk files (required):
Source code:

The Input Observer requires the Microsoft .NET 4.0 Framework. Download it here.
This software is distributed under the New BSD License agreement.


The Input Observer is an application that runs quietly in the background and gathers data on a user's mouse pointing and text entry performance from everyday computer use. The Input Observer measures text entry speed, uncorrected errors, and corrected errors. It is capable of distinguishing between unintentional errors and intentional edits. The Input Observer also measures pointing speed, error rate, and Fitts' law throughput, normalized using Crossman's (1957) effective target parameters. The Input Observer does all of these things without a task model or any ground truth about a user's intentions. The Input Observer may be useful to device manufacturers, researchers, interaction technique developers, and assistive technology therapists for understanding how input technologies fare "in the wild."

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Evans, A.C. and Wobbrock, J.O. (2012). Taming Wild Behavior: The Input Observer for Obtaining Text Entry and Mouse Pointing Measures from Everyday Computer Use. Proceedings of the ACM Conference on Human Factors in Computing Systems (CHI '12). Austin, Texas (May 5-10, 2012). New York: ACM Press, pp. 1947-1956.

Evans, A. and Wobbrock, J.O. (2011). Input Observer: Measuring text entry and pointing performance from naturalistic everyday computer use. Extended Abstracts of the ACM Conference on Human Factors in Computing Systems (CHI '11). Vancouver, British Columbia (May 7-12, 2011). New York: ACM Press, pp. 1879-1884.


This work was supported in part by the National Science Foundation under grant IIS-0952786. Any opinions, findings, conclusions or recommendations expressed in this work are those of the authors and do not necessarily reflect those of the National Science Foundation.

Copyright © 2011-2013 Jacob O. Wobbrock. All rights reserved.
Last updated June 25, 2019.